1. Field of the Invention
This invention relates to an inflatable tube i.e. a hollow tube of, for example, polymer-coated fabric material, that is suitable for use, for example, as a buoyancy tube for an inflatable liferaft.
2. Description of the Related Art
An inflatable liferaft usually has one or more buoyancy tubes around its perimeter, the tube or tubes supporting the raft and one or more occupants in a floating condition. The or each tube is bent or folded at appropriate positions so in plan, the liferaft is polygonal e.g. hexagonal or octagonal.
In U.S. Pat. No. 4,472,225 to Bimpson there is described a method of making a length of inflatable tube with a bend in it, which includes the steps of overlapping and joining the longitudinal edges of a suitable sheet of material to form a flattened tube, marking on one surface of the flattened tube a fold line corresponding to the desired position of the bend, marking one on each side of the fold line, two areas of the fabric that are to be pressed together to form the bend, folding the flattened tube so that the said two areas contact each other, joining said two areas together and sealing the ends of the tube. The preferred method of joining the said two areas is by a welding technique, although adhesive could be used if desired. The welding is carried out by any conventional method including heat-, high frequency-, or radio frequency-welding techniques.
However it has been found that due to the permanent nature of the joining methods referred to above, unwanted tensions etc are present in the fabric adjacent the bend with the result that a fault sometimes occurs.
It is an object of the present invention to substantially overcome or reduce the effects of this disadvantage.